Light bulb



FIG. 1 is a perspective view of a light bulb showing the new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken line showing of vents is included for the purpose of illustrating environmental structure and forms no part of the claimed design. 

CLAIM The ornamental design for light bulb, as shown and described. 